* src/cff/cffobjs.c (cff_face_init): Better handling of Type0 fonts.

This issue relates to the PDF specification and its usage of CFF-based
embedded Type0 fonts.  For Type0 fonts containing CID-keyed descendant
CFF-based fonts, the glyph index is the CID present in the content stream.
As a result, there is no requirement for a 'cmap' table to be present in the
font since the glyph indices are derived directly from the CIDs.  FreeType
throws an error when it doesn’t find a 'cmap' table for such an Open Type
font containing CFF outlines.  This commit relaxes this requirement for a
'cmap' table for such fonts.

src/cff/cffobjs.c

@@ -550,13 +550,13 @@
         if ( error )
           goto Exit;
       }
-      else
-      {
-        /* load the `cmap' table explicitly */
-        error = sfnt->load_cmap( face, stream );
-        if ( error )
-          goto Exit;
-      }
+
+      /* load the `cmap' table explicitly */
+      error = sfnt->load_cmap( face, stream );
+
+      /* this may fail because CID-keyed fonts don't have a cmap */
+      if ( FT_ERR_NEQ( error, Table_Missing ) && FT_ERR_NEQ( error, Ok ) )
+        goto Exit;
 
       /* now load the CFF part of the file; */
       /* give priority to CFF2              */